This invention relates to proteinaceous foods and more particularly to animal foods of the shelf-stable, intermediate-moisture variety.
Until the past decade, animal foods were sold either in dry or canned form. The dry variety of the animal foods usually contains less than 10% moisture and hence does not require sterilization procedures or refrigeration in order to render them resistant to microbial decomposition. The dry animal foods, however, are generally characterized by their low degree of palatability, it being found that as a general rule palatability is enhanced at higher moisture contents.
Canned animal foods enjoy a significant degree of palatability owing primarily to their high moisture contents, typically in the area of 75%. However, this high moisture content necessitates the sterilization of such products, generally by retorting, and refrigeration once the can is opened. Thus, canned foods involve significant processing costs and a lack of consumer convenience.
A significant contribution in the animal food field was made by Burgess et al. in U.S. Pat. No. 3,202,514. Therein is described a pasteurized intermediate-moisture animal food based principally upon proteinaceous meaty materials which product is shelf-stable and resistant to micobial decomposition without the need for sterilization, refrigeration or asceptic packaging. The meaty animal food is stabilized by water soluble solutes, principally sugar. The function of these solutes is to bind up available water in which microorganisms grow.
While the product of Burgess et al. represented a significant contribution to the state of the art, the need for improvement in this area has been and continues to be recognized. More specifically, prior art workers have attempted to improve the palatability of such products such that they achieve parity in this area with the more palatable canned animal foods. Palatability improvement may take a variety of forms, such as the overt addition of enhancers, the elimination of negative taste factors, the utilization of greater amounts of meaty materials, and increasing the moisture content.
Among the known negative factors in intermediate animal foods are certain of the stabilizers, especially when employed at relatively high levels. Thus, elimination or reduction in the level of these stabilizers would provide a boost in palatability. Moreover, reduction of the level of stabilizers required would also reduce costs, permitting a net savings or the use of more costly, flavorful ingredients in a product to be sold at the same price. Thus, by reducing the negative factors of the stabilizers, more of the positive factors of the animal food are allowed to exert their effect.
While the aforementioned Burgess et al patent relied mainly upon soluble solids, principle among which is sugar, and employed only relatively low levels of polyhydric alcohols, more recent teachings in the art have suggested the use of levels of polyhydric alcohols such as propylene glycol and butylene glycol in levels of from greater than about 4% to as high as about 20%. It is well recognized that such high levels of the polyhydric alcohols have a negative impact on the palatability of the animal foods, especially for dogs and cats. It would therefore be desirable to in some manner reduce the level of use of these stabilizers but still achieve the same level of stability obtained through the use of high levels of these materials.
It is therefore an object of the present invention to decrease the level of polyhydric alcohols required to stabilize intermediate-moisture food products against microbial growth.
It is a more specific object of the present invention to decrease the level of polyhydric alcohols required to stabilize intermediate-moisture pet food products, especially those comprising pasteurized proteinaceous meaty materials, against microbial growth.
It is another object of the present invention to enable an increase in the levels of the more positive factors, such as meat, water, or nutritional supplements present in the pet food.
This and other objects are accomplished by the present invention which provides an improved process for preparing an intermediate-moisture food product wherein a polyhydric alcohol is employed as an antimicrobial, wherein the improvement comprises:
packaging said food in a substantially gas impervious packing material, and filling the free space in the package with carbon dioxide.